Alternating-current meter.



No. 698,674. Patented Apr. 29, I902.

T. DUNCAN.

ALTERNATING CURRENT METER.

(Application flied. Nov. 24, 159% 2 Shuts-Sheet I.

( No Model.)

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No. 698,674. I Patented Apr. 29, I902.

T. DUNCAN.

ALTERNATING CURRENT METER.

(Application filed Nov. 24, 1899..) (No Model.) I 2 Sheets-Sheet 2.

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UNITED STATES PATENT OFFICE.

TIIOMAS DUNCAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE SIEMENS & I-IALSKEELECTRIC COMPANY OF AMERICA, OF CHICAGO, ILLINOIS, A

CORPOR ATION OF ILLINOIS.

ALTERNATlNG-CURR-ENT METER.

SPECIFICATION forming part of Letters Patent No. 698,674, dated. April29, 1902. Application filed November 24, 1899. Serial No. 738,172.(Noniodeh) To aZZ whom, it may concern:

Be it known that I, THoMAs'DUNo N, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois,

have invented a certain new and useful Improvement inAlternating-Current Meters, (Case No. 325,) of which the following is afull, clear, concise, and exact description, reference being bad to theaccompanying drawings, forming a part of this specification.

My invention relates to motor-meters, and has forits object theprovision of an improved watt motor-meter for measuring alternatingcurrent in a multiphase system of electrical distribution. I

My invention in its preferred embodiment is adapted-to measure thecurrent in a threephase three-wire system of alternating-currentdistribution.

In practicing my invention I preferably employ three current-windings,each transmission-conductor furnishing a winding with current. theinvention these current-windings create three fields which areproportional to and vary in phase with the three currents of the system.Assuming that the system is balanced, these fields are displaced onehundred and twenty degrees from each other. In practicing my invention Ihave also included two field-coils of the system together in series withsecondary windings of transformers receiving current from two mains ofthe system, whereby the resultant of the two currents in the secondariesof the transformers caused a single field. I associate a pressurewindingwith one of the current-windingsto produce a field proportional to aresultant of two pressures of the system, which field, in cooperationwith the field due to said currentwinding, is capable of creating atorque upon the measuring element. I associate a second pressure-Windingwith the remaining two current field windings or coils to produce afield which, in cooperation with the field or fields due to these twocurrent-coils, creates another torque upon the measuring element. Thetwo torques act conjoiutly upon the measuring element to produce motiontherein, which measures the real or true watts In the preferredembodiment of of the three-phase system irrespective of the conditionsof load and at 'all power factors. In the preferred embodiment of myinvention I employ an induction-motor as an element of the instrument,two armatures being preferably employed, onein-inductive relation withthe first aforesaid pressure-winding and its associated current fieldwinding, while the other is in inductive relation with the secondpressure-winding and the two remaining current field-coils cooperatingtherewith.

The two armatures are mechanically coupled, being preferably mountedupon a common :shaft, which serves to actuate a measuring device orrecording-train.

I will explain my invention more particularly by reference to theaccompanying drawings, illustrating preferred embodiments thereof asapplied to induction motor-meters, in Which Figure 1 diagrammaticallyillustrates a three-phase system of electrical distribution with themeter of my invention connected therewith. Fig. 2 diagrammaticallyillustrates a three-phase system of electrical distribution forsupplying heavy current at high voltage with the meter of my inventionassociated therewith. Figs. 3 and 4 are phase and vector diagramsillustrating the electrical principles involved.

Like parts are indicated by similar characters of reference in all theviews.

A three-phase alternating-current generator 1 supplies current by threeconductors to a district of consumption, a motor 2 being shown as atranslating device in circuit therewith. Two cup-shaped armatures 3 and4. are indicated in this instance, these armatures being mounted upon acommon rotating shaft or spindle 5. The instrument illustrated in thisinstance is a recording andintegrating meter, a counting-train 6 beinggeared to the spindle. A series or current winding 7 is indicated incircuit with atrans mission-main 8, as shown in Fig. 1, or is includedin circuit with the secondary of a transformer 9, whose primary isincluded in series with the conductor 8, as shown in Fig. 2. Thecurrent-winding 7 is preferably divided into two coils located,preferably, upon diametrically opposite sides of the armature 3.

Referring to Fig. 1, a second current-coil is included in series withthe transmissionconductor 11. A third current-winding 13 is included inseries with the transmissionconductor 14. Assuming that the system isbalanced, the resultant field due to the coils 10 and 13 is displacedsixty degrees in phase from the current in either of the said coils. Thearrangement of the current field-coils 1 0 and 13 of the apparatus shownin Fig. 2 difiers from the arrangement shown in Fig. 1 in that twotransformers 12 and 15 are em ployed, the secondaries of thesetransformers and the current-windings 10 and 13 being illcluded inseries 'in a single circuit. One armature 3 is inductively associatedwith the coils of one field-winding 7, while the armature 4 isinductively associated with the coils 10 and 13.

To create a field proportional to the electromotive force to cooperatewith the field due to the winding 7, Iconnect one end of ashuntconductor 16 with a main 8, the other end of the conductor beingconnected with a compensating winding 19 about midway between the endsthereof, this compensator being connected in bridge of the mains 11 and14. The winding 19 is shown in Fig. las being non-inductive and of highresistance. In Fig. 2 the winding 19 is arranged in the form of animpedance-coil. By this means I am enabled to impress an electromotiveforce upon the conductor 16, which is in phase with the current inconductor 8, itbeing assumed that there is no reactance in the system.

In the form of the invention shown in Fig. 1 the pressure-winding 20 isincluded in metallic circuit with the bridge conductor 16. In Fig. 2 thesaid pressure-winding is shown as being included in circuit with thesecondary of a transformer 21, whose primary is included in metalliccircuit with the bridge conductor 16. In Fig. 1 pressure-winding 20 isformed in one coil, while in Fig. 2 the said pressure-winding issubdivided into two coils, placed upon opposite sides of the armatureand at right angles with respect to the coils 7. The instrument shownbeing an induction motor-meter, it becomes essential to secure a phasedisplacement of the pressure field ninety degrees away from the pres-'sure impressed upon the circuit including the pressure-winding, orninety degrees away from the field due to the current-winding, therebeing no reactances in the transmissionconductors, for whichpurpose avariety of' means may-be employed.

I have shown in both figures reactance in the form of an impedance-coil22, included in series with the pressure-winding 20, to lag the currenttherethrough to as near ninety degrees as possible.

To obtain exact quadrature between the pressure field and the pressureimpressed upon the circuit including the pressure-winding, I mayemploy asecondary winding 23, constituting a single coil in the apparatus ofFig. 1 and being subdivided into two coils in the apparatus shown inFig. 2, the secondary windings being inductively associated with thepressure-windings 20. The winding 23 is preferably short-circuitedthrough an adjusting non-inductive resistance 24. By adjustment of theresistance 24 a resultant magnetic pressure field may be produced thatwill have the required phase displacement.

I will now describe the pressure-winding associated with thecurrent-windings 10 and 13.

A conductor 25 is shown in each figure as being in bridge between thetransmissionconductors 11 and 14. In Fig. 1 the pressure or shuntfield-winding 26 is included in the conductor 25, while in Fig. 2 thesaid conductor includes the primary coilof a transformer 27, thesecondary of said transformer being included in circuit with thepressure-winding 26. In Fig. 1 the pressure winding 26 is formed in asingle coil, while in Fig. 2 said winding is subdivided into two coilsplaced upon opposite sides of'the armature 4 and at right angles withrespect to the current-coils 10 and 13. The pressure impressed upon thecircuit including the pressure-winding 26 is in phase with the resultantfield due to the coils 10 and 13, these coils forming a single winding,producing a resultant field-that is, either of the coils 10 or 13 isreversely connected in order to effect the desired measurement, as willbe more fully setforth hereinafter. I preferably include impedance 28 inseries with the said pressure-winding 26 to lag the current through thesame as near ninety degrees as possible away from the pressure betweenthe conductors 11 and 14. To create a pressure field in exact quadraturewith this pressure, I'employ a secondary winding 29 and short-circuit itthrough an adjusting resistance 30. By adjusting the resistance 30 exactquadrature may be ob tained between the pressure field and the pressure.In Fig. 1 I have shown the winding 29 formed of a single coil. In Fig. 2said winding is shown as being subdivided into two coils, the adjustingresistance 30 being included in series with them.

The current and pressure relations will be more clearly understood byreference to Figs. 3 and 4. In these figures, a, b, and c represent thecurrents in the conductorsll, 14, and 8, respectively. The pressureimpressed on thecircuit 16 is in phase with the current in conductor 8and is represented by line 0, Fig. 3, with non-inductive loading of thesystem. The impedance-coil 22 serves to lag the current through circuit26, which current may be represented byline cl. To further lag the fieldthrough the said shunt-circuit, I employ the auxiliary coil 23,whosemagnetic efiect may be represented byline e. The resultant magnetism dueto the circuit 16 is then indicated by linef and is in quadrature withthe current through series winding 7, as represented by line 0, Fig. 3.Referring now to Fig. 4, I

have indicated the connections of coil lOas reversed, so that themagnetic effect of the said coil may be represented by the dotted linea. The resultant field due to the two current-coils 10 and 13 would,therefore, not lie along a line one hundred and eighty degrees displacedfrom the current in the con ductor S, but would lie along a line g,which is in quadrature therewith. The pressure impressed upon thecircuit 25 is represented by line 71, which is parallel to the resultantseries field g. In order to secure an actuation of the measuringelement, I lag the current through said circuit by means of theimpedance 28 and the auxiliary coil 29, so that the magnetic eifect dueto said circuit 25 may represented by the line 1', which is inquadrature with the resultant series field g.

I am thus enabled to produce a meter fora three-phase system ofalternating-current distribution employing field-windings supplied withcurrent from the three transmissionmains of the system-and twopressure-windings associated with these field-windings, which incooperation therewith are adapted to create two torques adapted toactuate a measuring element to measure the power in the system. In theapparatus of Fig. 2 it is understood, of course, that the relative phaserelations of the resultant fields remain unchanged, the transformersserving simply to substantially reverse all of the currents in thesecondary circuits, the latter being displaced approximately one hundredand eighty.de-.

grees from the primary currents. Any irregularities in the phaserelations due to losses in the transformers may be compensated for bythe readjustment of the various resistances and reactances employed.

It will of course be understood that only one of the two armatures,together with its associated windings, will correctly measure.

the energy consumed in the system so long as the system is balanced, andmy invention contemplates the use of only one of the said armatnres,together with its associatedwindings, or, in other words, only one ofthe two elements which go to make up the meter, .as illustrated in thedrawings; but when the system becomes unbalanced then, because themeter-windings are included in only one or two of the three-phase mains,the meter will no longer register accurately; I therefore prefer toconstruct the meter with a current-coil connected in eachof the threemains, so that any change in load in either of the branches of thesystem will change the current-flow in one or more of themeter-windings, with the result that an accurate measurement of theenergy consumed is effected under all conditions.

It is obvious that changes may readily be made in the preferredembodiments of my invention herein shown and particularly described, andI do not therefore wish to be lim' ited to the precise details shown;but,

Having thus described my invention, I

claim as new and desire to secure by Letters Patent 1. In a three-phasesystem of alternatingcurrent distribution, the combination with acurrent-winding supplied with current from one of thetransmission-conductors, of asecond current field-winding supplied withcurrent from the remaining transmission-conductors, a pressure-windingassociated with each of said current-windings, a measuring elementsubjected to the action of. the fields due to the said windings, andmeans associated with the circuits including'the pressurewindings formaintaining the fields due to the pressure-windings substantially inquadrature with the pressure upon the circuits including the same,substantially as described.

.2. In a polyphase system of electrical dis-..

tribution, the combination with a source of polyphase alternatingcurrent, of transmission-conductors for conveying polyphase cur-' rents,acurrent-winding producing. a field proportional to the current in onetransmission-conductor, a pressure-winding produc-' ing a fieldproportional to the resultant of two pressures impressed on saidtransmissionconductors, the said two windings'serving conjointly toexert torque upon an armature, a second current-winding producing afield proportional to the resultant of two currents of displaced phasetraversing said transmis: sion-conductors, a second pressure-windingproducing a field proportional to the pressure of one of the circuitsimpressed on said transmission-conductors, the last two aforesaidsultant of two out-of-phase currents travers:

ing two separate transmission-conductors, a

second pressure-winding producing a field proportional to the pressureof acircuit impressed on said transmission conductors, a measuringelement inductively associated with said field-windings to measure thepower ofthe system, and means for maintaining the fields due to thepressure-windings in quad rature with the pressures impressed .on theirrespective circuits,substantially asdescribed.

4E. In a system ofValternating electric-current distribution, thecombination with a source of three-phase alternatingcurrent in circuitwith the three transmission-mains of the system, of a currentfield-winding receiv; ing current from one of the mains, a compen-.

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their conjoint action serving to exert torque upon said armature,substantially as described.

5. In a system of alternating-electric-current distribution, thecombination with a source of three-phase alternating current in circuitwith the three transmission-mains of the system, of a currentfield-winding receiving current from one of themains, a compensator 19between the remaining two mains, a

conductor 16 receiving current from said compensator and the firstaforesaid transmissionmain, a second field-winding receiving its currentfrom said conductor, a motive element inductively acted upon by thefields due to the field-windings, and means for adjusting the phaserelation of said fields, substantially as described.

6. In a system of alternating-electric-current distribution, thecombination with a source of three-phase alternating current in circuitwith the three transmission-mains of the system, of a currentfield-winding receiving current from one of said mains, a com pensatorbetween the remaining two mains, a conductor extending between anintermediate portion of said compensator and the first aforesaidtransmission-main, a second field-winding receiving its current fromsaid conductor, and a motive element subjected to the action of saidfields, substantially as described.

7. In a system of alternating-electric-current distribution, thecombination with a source of three-phase alternating current in circuitwith the three transmission-mains of the system, ot-a currentfield-winding receiving current from one of said mains, a compensatorbetween the remaining two mains, a conductor extending between anintermediate portion of said compensator and the firstaforesaidtransmission-main, a second field-winding receiving its currentfrom said conductor, a motive element inductively acted upon by thefields due to the field-windings, and means for adjusting the phaserelation of the fields, substantially as described.

-8. In a system of alternating-current distribution, the combinationwith two conductors, of means for supplying the same with alternatingcurrents diltering in phase, a ourrent field-winding supplied withcurrent from each of said mains and serving to produce a field which isproportional to the resultant of the currents in said mains, a pressurefieldwinding serving to create a second field proportional to thepressure between said conductors, a movable element inductively actedupon by the fields due to the field-windings, and means for adjustingthe phase relation of the fields, substantially as described.

9. In a system of alternating-current distributiomthe combination with asource of three-phase current in circuit with the mains of the system,of a current field-winding supplied with out-of-phase currents from-twoof the mains and serving to produce a field proportional to theresultant of the currents in the latter mains, a pressure field-windingserving to create a field proportional to the pressure between thelatter two windings, a

movable elementinductively acted upon by the fields due to thefield-windings, and means for adjusting the phase relations of thefields,

substantially as described.

10. In a system'of electrical distribution,

the combination with a source of three-phase currentin circuit with thethree transmissionmains of the system, of a current field-windingreceiving current from one of the mains of the system, a pressurefield-winding adapted to create a pressure field proportional to theresultant of the pressures between the latter main and each ofthe othermains of the system, a second current-winding receiving current fromeach of the remaining mains of the system and serving to create a fieldproportional to the resultant of the currents in the latter mains, asecond pressure-winding for creating a field proportional to thepressure between the latter mains, and a mess uring element subjected tothe action of said fields to measure the power of the system,substantially as described.

11. In a system of electrical distribution the combination with a sourceof three-phase current in circuit with the three transmissionlnains ofthe system, of a current field-winding receiving current from one of themains of the system, a pressure field-winding adapted to create apressure field proportional to the resultant of the pressure between thelatter main and each of the other mains of the system, a secondcurrent-winding receiving cur rent from each of the remaining mains ofthe system and serving to create a field proportional to the resultantof the currents in the latter mains, a second pressure-winding forcreating a field proportional to the pressure between the latterrmains,an armature associated with the first two field-windings, and a secondarmature subjected to the second two field-windings to measure the powerof the system, substantially as described.

12. In a'system of electrical distribution, the combination with asource of three-phase currentin circuit with the three transmissionmainsof. the system, of a current field-winding receiving current from one ofthe mains of the system, a pressure field-winding adapted to create apressure field proportional to the resultant of the pressure between thelatter mains and each of the other mains of the system, a secondcurrent-winding receiving current from each of the remaining mains ofthe system and serving to create a field proportional to the resultantof the currents in the latter mains, a second pressure-winding ICC -mains of the system, of a current field-winding receiving current fromone of the mains of the system, a pressure field winding adapted tocreate a pressure field proportional to the resultant of the pressuresbetween the latter'main and each of the other mains of the system, asecond current-'Winding receiving current from each of theremainingmains of the systemand serving to create a field proportional to theresultant of the currents in the latter mains, a second pressure-windingfor creating a field proportional to the pressure between the lattermains, a measuring elementinductively acted upon by said fields, andmeans for adjusting the phase relations of the fields, substantially asdescribed.

14. In a system of electrical distribution, the combination with asource of three-phase current in circuit with the threetransmission-mains of the system, of a current fieldwinding receivingcurrent from one of the mains of the system, apressure field-windingadapted to create a pressure field proportional to the resultant of thepressures between the latter mains and each of the other mains ofthe'system, a second current-winding receiving current from each of theremaining mains of the system and serving to create a field proportionalto the resultant of the currents in the latter mains, a secondpressure-winding for creating a field proportional to the pressurebetween the latter mains, an armature being inductively associated withthe said field-windings, a second armature subjected to the second twofield-windings to measure the power of the system, a measuringelement,said armatures being inductively associated with saidfield-windings to measure the power of the system, and means foradjusting the phase relations of the fields,sub-

stantially as described.

15. In a polyphase system of electrical distribution, the combinationwith a source of polyphase alternating current, of a currentwindingproducing a field proportional to the current in onetransmission-cont]uctor,a pressure-winding producing a fieldproportional to and displaced substantially ninety degrees from theresultantof two pressures of the system, said windings servingconjointly to exert torque upon an armature, a second current-windingproducing. a field proportional to the resultant of two currents of. thesystern, a second pressure-winding producing a field displacedsubstantially ninety degrees from the pressure of one circuit of thesystem, said pressure-winding receivingits current from the two mains ofthe system including the coils of the last aforesaid currentwinding, anda measuring element subject to the action of said fields to measure thepower 0f the system, substantially as described.

16. In a'polyphase system of electrical distribution, the combinationwith a source of polyphase current, of a current-winding producing afield proportional to the current in one transmission conductor,-apressure-winding producing a field proportional to the resultant of twopressures of the system cooperatively associated with saidcurrent-winding, an armature subject to-the torque created by theconjoint action of said fields, a

second current-winding producing an effective field proportional to theresultant oftwo currents of the system, a second pressurewindingproducing a field proportional to the stantially as described.

17. In a three-phase, system of electrical distribution, the combinationwith a source of three-phase alternating current, of a current-windingproducing'a field proportional to the current in onetransmission-conductor, a pressure-winding producing a fieldproportional to the resultant of two pressures of the systemcooperative] y associated with saidcurrent-winding, a secondcurrent-winding producing a field proportional to the resultant of twocurrents of the system, a second pressure-winding producing a fieldproportional to the pressure between the two remainingtransmission-conductors of the system associated with said secondcurrent-winding, the

said second pressurewinding receiving its .current from the mainsincluding the coils of the second current-winding and a measuringelement subject to the torque produced by .the first aforesaid set offields and also to the torque of the last aforesaid set of fields, sub-.stantially as described.

18. In a three-phase system of-electrical distribution, the combinationwith a source I of three-phase current, of a motor-meter having twoarmatures, a current field-winding supplied with current from oneofthe'transmission-conductors associated withone of a sociated with eachof said current-windings,

the pressure-winding associated with the last aforesaid. currentfield-winding receiving its current from the two transmission-conductors of the system including the coils of the said second currentfield-winding, substantially as described.

19. In a polyphase system of alternatingcurrent distribution, thecombination with a current-winding supplied with current from saidsystem, of a compensator connected .be-

tween two of the mains, a pressure-winding cooperatively associated withsaid currentwinding receiving its current from a conductor extendingbetween an intermediate portion of said compensator and a transmis-.sion-main, means for maintaining the field due to the pressure-windingsubstantially in quadraturewitli the pressure impressed on its circuit,and a measuring element subject to the action of said fields,substantially as described.

20. In a system of alternating-current distribution, the combinationwith a source of three-phase current in circuit with the mains ot' thesystem, of a current field-winding supplied with out-of-phase currentsfrom two of the mains and serving to produce a field proportional to theresultant of the currents in the latter mains, a pressure field-windingserving to create a field proportional to the pressure between thelatter two windings, a movable element subject to the conjoint action ofsaid windings, and means for maintaining the field due to thepressure-winding in quadrature with the pressure impressed on theterminals of the pressure-circuit, substantially as described.

21. In a system'of polyphase-alternatingcurrent distribution, thecombination with a source of current connected to transmissionmains, ofa current field-winding receiving current from one main of said system,a pressure-winding receiving its current from said main and associatedmains, thereby to create a field proportional to the resultant of twopressures of the system, and an armature subject to the conjoint actionof said fields, substantiallyas described.

22. In a polyphase system of electrical distribution, the combinationwith a source of polyphase current, of a current-winding producing afield proportional to the current in one transmission-00nductor, apressure-windducing a field proportional to the pressure of one circuitof the system, the said second' mains, of acurientfield-windingreceiving current from one main of said system, apressure-windingreceiving its current from said main. and associatedmains,thereby to create a field proportional to the resultant of twopressures of the system, an armature subject to the conjoint action ofsaid fields, and means for maintaining the field due to thepressure-winding in quadrature with the pressure impressed on theterminals of the pressure-circuit, substantially as described.

24. In an induction-meter for three-phase circuits, a maincurrent-winding comprising a plurality of sections suitably connected tothe three-phase mains, a shunt-winding connected across points, thepotential between which is in, phase with the resultant of the currentsin the sections of the main currentwinding on non-inductive load, andmeans for causing the magnetic field due to the shunt-winding'to'bedisplaced by substantially ninety degrees from electromotive forceimpressed upon the shunt-circuit.

25. In an induction-meter for three-phase circuits, a maincurrent-winding comprising a plurality of coils eachconnected in circuitwith one of the three-phase mains, a shuntwinding connected between twoof the mains, and means for causing the field due to the shunt-windingto be displaced by substanstantially ninety degrees from theelectromotive force impressedupon the shunt-circuit.

26. In an induction-meter, for three-phase circuits, a maincurrent-winding comprising two coils each connected in circuit with oneof the three-phase mains, a shunt winding connected between the mains inwhich the series coils are included, and means for causing the field dueto the shunt-winding to be displaced by substantially ninety degreesfrom the electromotive force impressed on the shunt circut. i

In witness whereof I hereunto subscribe my name this 22d day ofNovember, A. D. 1899.

THOMAS DUNCAN.

\Vitnesses:

WM. F. MEYER, JAMES W. DALTON.

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